Method of preparing a solid semi-moist marbled meat pet food



United States Patent 3,380,832 METHOD OF PREPARING A SOLID SEMI-MOISTMARBLED MEAT PET FOOD David P. Bone, Palatine, 11]., assignor to TheQuaker Oats Company, Chicago, 111., a corporation of New Jersey NoDrawing. Continuation of application Ser. No. 477,940, Aug. 6, 1965.This application Dec. 23, 1966, Ser. No. 604,489

9 Claims. (Cl. 99-7) This application is a streamlined continuation ofapplication Ser. No. 477,940, filed Aug. 6, 1965, now abandoned.

This invention relates to a meaty pet food having the appearance andtexture similar to raw meat which is marbled throughout with fat.

An object of this invention is to provide a meaty pet food, (i.e., onecontaining substantial amounts of meat or meat by-products) of thesemi-moist type containing 20% to 50% moisture and having the appearanceof marbled meat. Another object of this invention is to provide aprocess by which a meaty pet food can be colored and formed to simulatedifferent kinds and cuts of meat having varying degrees of marbling withor without an overlay having the appearance of fat. A singularlyimportant object of this invention is to provide a processed meaty petfood which ranks very high in palatability and acceptability to animals.

These and other objects which will be apparent hereinafter areaccomplished by the product and method of this invention. This productis a meaty substantially solid semi-moist animal food resembling marbledmeat comprising a red portion and a white portion, said red portioncontaining a caseinate salt binder in an amount sufficient to causetackiness at temperatures above 120 F., said white portion beingrandomly distributed in the red portion, and said red and white portionsbeing joined to form an integral mass having substantially distinctinterfaces between said portions.

The method for the manufacture of a semi-moist animal food resemblingmarbled meat comprises the following steps: (a) extruding by acooking-extrusion process a first sheet of unexpanded storage-stablesemimoist animal food having the appearance of lean red meat andcontaining a caseinate salt adhesive in an amount sufficient to providestickiness at temperatures above 120 F.; (b) extruding by acooking-extrusion process a second sheet of unexpanded storage-stablesemi-moist animal food having the appearance of fat, saidcooking-extrusion process comprising the steps: (1) admixing comminutedanimal food ingredients which include a total moisture content betweenabout 20% and about 50%, said ingredients having been selected toprovide a substantially solid, storage-stable nutritious pet food aftercooking the resulting admixture, (2) subjecting the resulting admixtureto cooking conditions at a superatmospheric pressure sufiicient toprevent substantial expansion of the resulting plastic mass in theextruder, and (3) extruding the resulting plastic mass through a dieinto the atmosphere; (c) superimposing one of said sheets on the other;and (d) forming superimposed sheets into a loaf-like mass, said formingbeing done in such a manner as to distribute randomly the fat-likeportion in the resulting mass, said forming taking place while theaverage temperature of said first and second sheets is between about 120F. and about 170 F.

The selection of specific nutritive ingredients to provide asubstantially solid, storage-stable, nutritionally balanced pet food iswell within the purview of one with ordinary skill in the art. Specificformulations are presented hereinafter, however, to illustrate severalpreferred embodiice ments of this invention. The preferred adhesive foruse in this invention is sodium caseinate. This adhesive, which isnutritious and relatively stable at extruder-cooker conditions, ispreferably admixed with the other ingredients prior to the cooking andextrusion in an amount greater than 7 /2% by weight based on the weightof the ingredients. However, other caseinate salts can be used, such asthose of calcium and potassium.

I have discovered that the inclusion of the caseinate adhesive in thesemi-moist pet food ingredients prior to the cooking-extrusion stepprovides an extrudate which is tacky, or sticky, at temperatures aboveabout F. (The minimum amount of caseinate required to provide stickinessdepends on the specific ingredient formulation selected, and can bereadily determined by adding different amounts to small trial batches.)I have also discovered that such extrudate, after being shaped intosheets, may be formed into marbled meat-like loaves by merely bringingthe sheets in contact with each other at temperatures above about 120 F.to provide a novel pet food product which is structurally stable and hasno significant tackiness at room temperature and at temperaturesnormally contemplated during storage. While it is essential that the redportion contain the specified amounts of the caseinate binder, it ismore preferred that both red and white portions contain the binder. Ihave also discovered, however, that the step of forming the superimposedextrudate sheets into a loaf-like mass must be carried out at atemperature below about F. or the resulting product will not resemblemarbled meat. At temperatures above 170 F., the forming step results ina bleeding or infusion of the lean meat-like layer into the fat-likelayer and vice versa, and the marbling appearance is substantially notachieved. The average temperature of the sheets may be measured, forexample, by forming the sheets into a baseball-sized wad and inserting athermometer into the wad.

While the dimensions of the first sheet referred to above are notcritical, it may be a continuous or perforated sheet-like extrudatehaving a width from several inches to many feet, and preferably athickness between about inch and about /2 inch. The dimensions of thesecond sheet are not critical also, except, as indicated below, thesecond sheet preferably covers less than half the contacted surface ofthe first sheet. It also may be continuous, discontinuous or perforatedand is incorporated into the finished product in an amount up to about45% by weight of the finished product, However, in the production of abeefsteak-like product, it is preferred that the second fatlike sheet beused in an amount between about 15% and about 25% by weight in theinterior portions of the roll or cut, and it is usually preferred thatan overlay of approximately /4 inch be laid down at the circumference ofthe roll. In the manufacture of a ham-like product, it is preferred thatthe second sheet be used in an amount between 5 and 10% by weight of theinterior or central portions of the roll and it is usually preferredthat an overlay of approximately /4 inch be laid down On thecircumference of the roll. Whenever a fat-like overlay is used, it isessential that the fat-like extrudate used in the overlay contain thecaseinate adhesive in an amount suflicient to provide stickiness attemperatures above 120 F., and that the average temperature of the sheetbe between 120 and 170 F. when being laid down.

Steak-like cuts can be prepared by slicing rolls of appropriatediameter; cuts resembling chops are prepared by slicing smaller diameterrolls or loaves which may have a relatively heavy fat-like overlay. Themost preferred form of the product of this invention is obtained byslicing the loaves into cubes approximately /2 inch on an edge.

While a loaf can be formed around a prefabricated bone-like structure,the preferred products of this invention are boneless. If a structureresembling bone is used, it must be either inert with respect to waterpick-up, or it must have approximately the same water activity as thesurrounding material.

In the practice of this invention it is essential that the fat-likeextrudate be distributed randomly through the product except for theoverlay referred to above. In the practice of this invention variousmethods of forming the superimposed sheets into a loaf-like mass may beemployed, therefore, providing the method results in the substantiallyrandom distribution of the fat-like portion through the product. Acertain degree of randomization is accomplished by forming a fat-likeextrudate sheet of inconsistent and irregular thickness. Also, a certaindegree of the randomization can be accomplished by superimposing thefat-like extrudate on the lean meat-like extrudate sheet in an irregularor random pattern. It is preferred that the fat-like extrudate sheethave a width less than half the width of the lean meatlike sheet andthat the fat-like sheet be distributed in an irregular random fashion onthe extrudate sheet. In a preferred embodiment, several narrow ribbonsof fatlike extrudate are laid down on a wide sheet of red extrudate. Itis preferred that the superimposed fat-like sheet cover much less thanhalf of the contacted surface (normally the top surface) of the leanmeat-like extrudate sheet. As indicated above, the fat-like sheet may becontinuous, discontinuous and/ or perforated. Also, the extrudates canbe flattened or smeared into a sheet-like shape. Perforation-likeirregularities can be achieved by extruding the fat-like portion in sucha manner that large bubbles of steam are formed upon extrusion so thatcrater-like depressions result when the bubbles burst, or collapse. Themore randomization that is accomplished when the fat-like sheet issuperimposed on the lean meat-like sheet, the less the randomizationwill be required when the superimposed sheets are formed into aloaf-like mass. Also, the superimposing step and the loaf-forming stepcan be performed simultaneously.

The forming of the superimposed sheets into a loaflike mass may beaccomplished in accordance with this invention by several methods, suchas, for example, (a) permitting the superimposed sheets to form a randompile beneath the end of the conveyer and compressing this tangled pileinto a wad, (b) catching the superimposed sheets in a forming means,such as a pan, while the first and second sheets are at the specifiedtemperatures and thereafter permitting the randomly distributed layersto integrate as a result of their own plasticity weight, and tackiness,and (c) rolling the superimposed sheets into a roll.

In the preferred embodiment of this invention in which the superimposedsheets are rolled into a roll, little additional randomization may benecessary during the rolling step if a high degree of randomization wasachieved during the step of superimposing the first and second sheets.However, it is generally preferred that when the superimposed sheets areformed into a roll, they be randomly laid down in a zone along theperiphery which is at least twice the width of the red sheet. Hence, ifa 4-inch wide ribbon or sheet of lean meat-like extrudate is beingutilized, a minimum size loaf to be formed by the preferred rollingembodiment would be approximately 8 inches. On the other hand, forexample, a continuous roll may be formed by continuously laying a 3-inchwide lean meatlike sheet (on which the second fat-like sheet has beensuperimposed) across a 6 to 16 inch zone at the end of a continuouslyrevolving roll or loaf while continuously withdrawing the resultingformed roll at such a rate as to keep the roll between about inches andabout 10 inches in diameter. Occasionally, in this preferred embodiment,superimposed sheets coming off a conveyer, for example, may form looserandom piles or wads behind a retreating revolving roll. These wads ofextrudate are simply pushed into the end of the roll to incorporate theminto the loaf or roll, and the resulting loaf end is then wrappedrandomly by the oncoming superimposed sheetsas before. If' awiderdiameter roll is formed, it can be kneaded or worked down to a loaf ofdesired size, provided the diameter reduction is carried out while theinterior of the loaf is at a temperature between about F. and 170 F.Generally speaking, the surface or skin of the roll will quickly fallbelow this temperature so that the skin is no longer tacky. Also, aplurality of smaller rolls can be formed into a bundle? resembling abundle of distinct major muscles by contacting the rolls at atemperature between about 120 F. and 170 F., and applying sufficientpressure to convert them into an integral mass. The resulting bundle canbe overlaid with a fat-like layer, if desired, in the manner describedabove. Slices of such multi-roll bundles can resemble the multimusclecuts such as, for example, round steak.

The randomized laying down of the superimposed sheets into a roll isdone in such a way as to minimize the formation of air pockets in therolled product. In the description of the process of this invention,therefore, the term rolling is intended to connote that the sheets aremanipulated to cause contact in such a manner, e.g., with adequatepressure, to bring about adhesion with a minimum of air pockets and yetwithout substantial infusion of the white material into the redmaterial.

Generally, the formulation of a pet food to provide storage stability iswithin the purview of one skilled in the art. In the practice of thisinvention a preferred formulation with respect to storage stability isone in which the water activity of the product is less than 0.90 andalso contains an effective amount of mold inhibitor, such as sorbic acidor its salts. Water activity (a as used herein is defined as follows:

where f=fugacity of water vapor in the specified system f =fugacity ofpure water at the specified system temperature and 1 atmosphere totalpressure.

Fugacity is a well-known physical-chemical term adequately defined inany appropriate text, such as Physical Chemistry, Prutton and Maron(1949) p. 318. As is apparent to those skilled in the art, wateractivity in the desired range is achieved by including appropriatequantities of soluble materials such as sugars and glycols in theformulation.

We have found that formulations such as those listed in the numberedexamples following using sugar in an amount between about 15 and 30% andpropylene glycol in an amount between about 2 and about 10% and sorbicacid or its salts in amounts from 0.06 to 0.3% provide adequate storagestability for the products of this invention which contain moisture inan amount between about 20% and about 40% by weight based on the weightof the product.

The extrusion conditions in the method of this invention are such thatthe ingredients are cooked; preferably temperatures between 190 and 300F. are used in the extruder with the pressure in the extruder beingsufficient to prevent substantial expansion of the resulting plasticmass in the extruder. I have discovered that the use ofstarch-containing ingredients, such as cereals or cereal fractions suchas starch, are not essential to the practice of this invention in itsbroadest aspects. It is nonetheless preferred that the ingredientscontain at least /2 of 1% starch. I have discovered that While meaty petfoods produced in accordance with thisinvention which are devoid ofstarch have the necessary appearance and texture of marbled meat, theydo not have a preferred degree of structural stability at elevatedstorage temperatures, i.e., above 120 F., e.g., F. to F. I havediscovered that including starch in an amount greater than /2 of 1% inthe ingredients prior to cooking provides a product which isstructurally stable to an eminently satisfactory degree under storageconditions at 135 F., provided temperatures in excess of 250 F. areachieved in the extruders, during the manufacture of the product.

As used herein, the term meaty indicates that a substantial portion ofthe ingredient list is made up of meat or meat by-products. The termmeat is understood to apply to the flesh of cattle, swine, sheep, goats,horses, whale and other mammals, poultry and fish. The term meatby-products includes such constituents as are embraced by that term inthe definitions of feed ingredients published by the Association ofAmerican Feed Control Ofiicials Incorporated. The following examples setforth certain preferred formulations for pet foods which embody theprinciples of the present invention. As used herein, the term parts andthe term percent (or refer to parts by weight and percent by weight,respectively.

Example 1 This example illustrates the manufacture of a beef-likemarbled meaty pet food which does not melt at 135 F.

The ingredients making up the base, and making up the marbling, werethoroughly mixed in separate blenders, in the proportion indicated inTable l.

Vitamin E Supplem Titanium Dioxide Riboflavin Supplemen Vitamin ASupplement (30,000 Irradiated Dried Yeast FD & C Red No. l. FD & CYellow No. 6

Total 109. 0000 100. 0000 The material referred to as Base in Table 1results in the first sheet referred to above as having the appearance oflean meat while the material referred to as Marbling in Table 1 resultsin the second sheet described above as having the appearance of fat. Thebase ingredients and the marbling ingredients were mixed separately andthe resulting mixtures were charged to separate extruders at such a ratethat the weight ratio of base extrudate to marbling extrudate wasapproximately 3:1. The conditions in the two extruders weresubstantially identical. The extruders were steam jacketed, and thecombination of friction and externally applied steam heat resulted inthe achievement of peak temperatures in the extruders in the range ofapproximately 260 F. to 275 F. The pressures utilized were adequate toprevent substantial expansion of the plastic mass within the extruder.Prior to expulsion from the extruder through the sheeting die, thecompressed plastic mass was forced through a cooling section consistingof a pipe-like projection from the end of the extruder with the resultthat the temperature of the plastic mass at the die was substantiallybelow the peak temperature range (260275 F. referred to above). Thiscooling step is desirable in that it minimized popping and spattering ofthe extrudate. The sheeting die utilized in the extrusion of the baseprovided an extrudate which was approximately 3 inches wide, andgenerally between and /2 inch thick. The die utilized in the extrusionof the marbling sheet provided an extrudate sheet which wasapproximately 1 /2 inch wide and likewise between about A and inch inthickness. Upon leavin the extruder, the extrudate develops largebubbles, e.g., in the order of from /2 to 1% inch in diameter which popleaving an irregular surface on the unexpanded extrudate. The firstsheet resulting from the extrusion of the base material was laid down ona moving conveyor belt and the second sheet resulted from the extrusionof the marbling ingredients was laid down on top of the first sheet onthe conveyor belt. The second sheet was laid down, however, in anirregular and nonuniform pattern by rolling, skipping and ballingportions of the second sheet prior to and/ or upon its contact with thefirst sheet. The purpose of this is to randomize the distribution of themarbling sheet on the lean meat-like first sheet in such a manner thatonly about a fourth of the surface of the first sheet was covered by thefat-like extrudate. The conveyor carried the superimposed sheets forsufficient length to permit the temperatures of the extrudates to dropto approximately -F. before the sheets were rolled into a roll. The rollwas formed in such a manner as to provide the shape of a long loafapproximately 3 feet in length. As this loaf was continuously revolvedaround its longitudinal axis, the superimposed extrudate sheets comingoff the conveyor were wound in random back and forth fashion until aloaf about eighth inches in diameter was formed. Several loaves of equalsize were prepared in this manner. The extrusion of the lean meat-likeportion was then terminated. The extrusion of the marbling portioncontinued, however, and each of the 3 foot by 8 inch loaves previouslyproduced were given an overlay of marbling portion between about A andabout /4 of an inch in thickness by replacing the loaf in the rollingdevice below the end of the conveyor and wrapping the fat-like extrudatearound the continuously rotating loaf.

These loaves were permitted to cool to approximately room temperature,at which time they were cut into steaks approximately of an inch inthickness. However, to faciiltate production rates, the loaves may beout immediately after forming, as desired. The steaks resembled marbledbeef in that the red, lean meat portion was marbled throughout in arandom fashion by the fat-like portion. Steaks produced in asubstantially identical manner were further cut into cubes approximately/2.' x /2" x A and fed to dogs in a feeding test in which the fresh beefstew meat cut into cubes of substantially the same dimensions was usedas a control. It was found that the product of this invention rankedequal to the fresh beef stew meat with respect to acceptability by theanimals.

Example 2 This example illustrates the production of a pet foodresembling ham in appearance. A batch of ingredients, hereinafterreferred to as base, and another batch of ingredients, hereinafterreferred to as marbling, were thoroughly admixed in accordance with theformulation specified in Table 2.

TABLE 2 Percent Base Marbling 29. 0 42. 5 13. 5 24. 2 24. 2 Caseinate15.0 150 Food Grade Dicaleium Phosphate-.. 2. 5 2v 5 Propylene Glycol.4. 5 4. 5 Salt l. 2 1. 2 Sodium Sorb 0. 1 0. 1 10. 0 10. 0

Ttoal 100. 00 100. 00

The thoroughly mixed ingredients were charged to separate extruders asin Example 1, except that the weight ratio of the quantity of base tomarbling was approximately 19:1. The extrusion conditions, the manner ofsuperimposing the extrudate sheets, the rolling of the extrudate sheetsand the overlaying of the resulting roll with a layer of marblingextrudate were carried out as indicated in Example 1 except that therandom superimposing of the fat-like sheet on the lean meat-like sheetcovered only about of the top surface of the lean meat-like sheet. Theloaf resulting from Example 2 was sliced into steaks. The sliced productwas observed to closely resembled hamsteaks. The products of bothExample 1 and Example 2 were subjected to stability tests in whichtemperatures of 135 F. were encountered, and it was found that theappearance and the structure of these products were substantiallyunchanged.

Example 3 In this example lower extrusion temperatures (i.e., ZOO-212F.) were utilized with a formulation which was devoid of starch with theresult that the resulting product reverted to an integral amorphousplastic mass when stored at temperatures between 120 F. and 135 F. eventhough at room temperatures the product had had the appearance andconsistency of marbled meat. In this example the formula utilized inExample 1 above was followed, except that the 7.5% corn starch wasreplaced by an equal additional quantitiy of sugar. The other conditionsof Example 1 were followed.

Generally speaking, I prefer the type of formulation specified in Table3 for use in accordance with this invention.

TABLE 3.PREFERRED FORMULATION It is noted that the meaty marblingportion of the ingredients illustrated in Examples 1, 2 and 3 abovecontain no red-meat ingredients. As used herein, the term sugar includessucrose, glucose, corn-syrup sugars, and the like. I have found that theaddition of from 0.2 to 0.4% titanium dioxide to the marblingingredients assists in the achievement of a white fat-like appearance.

Although the description of this invention has included considerabledetail, the particularity is not intended to limit the scope except asdefined in the appended claims.

Therefore, I claim 1. A method for the manufacture of asubstantiallysolid semi-moist animal food resembling marbled meatcomprising the following steps:

(a) forming by a cooking-extrusion process a first sheet of unexpandedstorage-stable semi-moist animal food having the appearance of lean redmeat, and having incorporated therein a caseinate-salt adhesive in anamounts sufficient to provide stickness at temperatures above 120 F.,said amount being between 7.5 and 25% by weight based on the weight ofthe first sheet,

(b) forming by a cookingextrusion process a second sheet of unexpandedstorage-stable semi-moist animal food having the appearance of fat,

said cooking-extrusion process of steps (a) and (b) comprising the stepsof:

(1) admixing comminuted animal food ingredients which include a totalmoisture content between about 20% and about 50%, said ingredientshaving been selected to provide a substantially-solid storagestablenutritious pet food after cooking the resulting admixture,

(2) subjecting the resulting admixture to cooking conditions at asuperatmospheric pressure suflicient to prevent substantial expansion ofthe resulting plastic mass in the extruder, and (3) extruding theresulting plastic mass through a die into the atmosphere,

(c) superimposing one of said sheets on the other,

and

(d) forming the resulting superimposed sheets into a loaf-like mass,said forming being done in such a manner as to distribute randomly thefat-like portion in the resulting mass, said forming taking place whilethe average temperature of said first and second sheets is between aboutand about 170 F.

2. A method as in claim 1 in which said second sheet contains acasein-salt adhesive in an amount suflicient to provide stickiness attemperatures about 120 F.

3. A method as in claim 1 in which said comminuted animal-foodingredients include a caseinate-salt adhesive in an amount greater than7.5% and starch in an amount greater than 0.5% by weight of the totalingredients and in which said cooking conditions include heating saidadmixture to a temperature between about 170 and about 300 F.

4. A method as in claim 1 in which said ingredients include meat or meatby-products in an amount between about 30% and about 70% sodiumcaseinate in an amount between about 7.5% and 25%, sugar in an amountbetween about 15% and about 30%, propylene glycol in an amount betweenabout 3% and about 6%, starch in an amount between about 0.5% and about10%, and color modifying agents; the amounts of said ingredients beingexpressed as percent by weight of the total ingredients.

5. A method as in claim 1 in which said forming step includes rollingthe superimposed sheets into a roll.

6. A method for the manufacture of a substantiallysolid semi-moistanimal food resembling marbled meat and exhibiting structural stabilityunder storage conditions at F., comprising the following steps:

(a) forming by a cooking-extrusion process a first sheet of unexpandedstorage-stable semi-moist animal food having the appearance of lean redmeat,

(b) forming by a cooking-extrusion process a second sheet of unexpandedstorage-stable semi-moist animal food having the appearance of fat,

said cooking-extrusion process of steps (a) and (b) comprising the stepsof:

(l) admixing comminuted animal-food ingredients which include a totalmoisture content between about 20% and about 50%, a caseinate salt in anamount sufficient to cause stickiness at temperatures greater than 120F., said salt being included in an amount between 7.5% and 25 watersoluble material in an amount sufficient to provide a product havingwater activity less than 0.9, and starch in an amount greater than 0.5%,the amounts of said ingredients being expressed as percent by weight ofthe total ingredients, said ingredients having been selected to providea substantially-solid storage-stable nutritious pet food after cookingthe resulting admixture,

(2) subjecting the resulting admixture to cooking conditions attemperatures in excess of 250 F. and at a superatmospheric pressuresufl'icient to prevent substantial expansion of the resulting plasticmass in the extruder, and (3) extruding the resulting plastic mass intothe atmosphere, (0) superimposing one of said sheets on the other, and(d) forming the resulting superimposed sheets into a loaf-like masswhile the average temperature of said first and second sheets is betweenabout 120 F. and

\I about 170 B, said forming being done in such a manner as todistribute randomly the fat-like portion in the resulting mass.

7. A method for the manufacture of a substantiallysolid semi-moistanimal food resembling marbled meat comprsing the following steps:

(a) shaping into a sheet-like shape a first extrudate of unexpandedstorage-stable semi-moist animal food having the appearance of lean redmeat and having incorporated therein a caseinate salt adhesive in anamount sufficient to provide stickiness at temperatures above 120 F.,said amount being between 7.5% and 25% by weight based on the weight ofthe first extrudate, thereby producing the first sheetlike shapes,

(b) shaping into sheet-like shapes a second extmdate of unexpandedstorage-stable semi-moist animal food having the appearance of fat,thereby forming the second sheet-like shapes,

(c) forming the first and second sheet-like shapes into a loaf-like masswhile the average temperature of said sheet-like shapes is between 120and 170 F., said forming being done in such manner as to distributerandomly the second sheet-like shapes in the resulting mass,

said first and second extrudates being produced by a cooking-extrusionprocess comprising the steps (1) admixing comminuted animal-foodingrediients which include a total moisture content between about 20%and about 50%, said ingredients having been selected to provide asubstantiaily-solid storage-stable nutritious pet food after cooking theresulting admixture,

(2) subjecting the resulting admixture to cooking conditions at atemperature between 170 and 300 F. and at a superatmospheric pressuresufficient to prevent substantial expansion of the resulting plasticmass in the extruder, and

(3) extruding the resulting cooked plastic mass into the atmosphere.

8. A method as in claim 7 in which said ingredients include sodiumcaseinate in an amount between 7.5% and 25%, sugar in an amount between15% and 30%, propylene glycol in an amount between 3% and 6%, starch inan amount between 0.5% and 10%, and a member selected from the groupconsisting of meat, meat by-products and mixtures thereof in an amountbetween 30% and 70%, the amounts of said ingredients being expressed aspercent by weight of the total ingredients.

9. A method for the manufacture of a substantially-- solid semi-moistanimal food resembling marbled meat comprising the following steps:

(a) smearing into a sheet-like shape a first extrudate of unexpandedstorage-stable semi-moist animal food having the appearance of lean redmeat, and having incorporated therein a caseinate-salt adhesive in anamount between 7.5% and 25% by weight based on the weight of the firstextrudate thereby providing a first sheet-like shape,

(b) extruding a fat-like extrudate of unexpanded storage-stablesemi-moist animal food having the appearance of fat,

(c) superimposing the fat-like extrudate on the first sheet-like shape,

(d) smearing the resulting superimposed extrudates into sheet-likeshapes,

(e) forming the resulting sheet-like shapes into a loaflike mass,

said superimposing and said smearing taking place while the averagetemperature of the first and second extrudates is above F., said formingtaking place while the average temperature of the sheets is between 120F. and F., said first and second extrudates being produced by acooking-extrusion process comprising the steps of:

(1) admixing comminuted animal-food ingredients which include a totalmoisture content between about 20% and about 50%, said ingredientshaving been selected to provide a substantially-solid storagestablenutritious pet food after cooking the resulting admixture,

(2) subjecting the resulting admixture to cooking conditions at atemperature between 170 and 300 F. and at a superatmospheric pressuresuflicient to prevent substantial expansion of the resulting plasticmass in the extruder, and

(3) extruding the resulting plastic mass into the atmosphere.

References Cited UNITED STATES PATENTS 2,802,737 8/1957 Anson et al 99107 2,813,025 11/1957 Anson et al. 99107 2,830,902 4/1958 Anson et al.99'-107 2,957,770 10 1960 Freund et al. 99107 2,964,409 12/1960 Sair99-l07 3,102,031 8/1963 MacAllister et al. 99-14 3,115,409 12/ 1963.Hallinan et al. 99-2 3,202,514 8/1965 Burgess et al. 99-2 3,320,0705/1967 Hartman 9917 RAYMGND' N. JONES, Primary Examiner.

H. H. KLARE, Assistant Examiner.

1. A METHOD FOR THE MANUFACTURE OF A SUBSTANTIALLYSOLID SEMI-MOISTANIMAL FOOD RESEMBLING MARBLED MEAT COMPRISING THE FOLLOWING STEPS: (A)FORMING BY A COOKING-EXTRUSION PROCESS A FIRST SHEET OF UNEXPANDEDSTORAGE-STABLE SEMI-MOIST ANIMAL FOOD HAVING THE APPEARANCE OF LEAN REDMEAT, AND HAVING INCORPORATED THEREIN A CASEINATE-SALT ADHESIVE IN ANAMOUNTS SUFFICIENT TO PROVIDE STICKNESS AT TEMPERATURES ABOVE 120*F.,SAID AMOUNT BEING BETWEEN 7.5% AND 25% BY WEIGHT BASED ON THE WEIGHT OFTHE FIRST SHEET, (B) FORMING BY A COOKING-EXTRUSION PROCESS A SECONDSHEET OF UNEXPANDED STORAGE-STABLE SEMI-MOIST ANIMAL FOOD HAVING THEAPPEARANCE OF FAT, SAID COOKING-EXTRUSION PROCESS OF STEPS (A) AND (B)COMPRISING THE STEPS OF: (1) ADMIXING COMMINUTED ANIMAL FOOD INGREDIENTSWHICH INCLUDE A TOTAL MOSITURE CONTENT BETWEEN ABOUT 20% AND ABOUT 50%,SAID INGREDIENTS HAVING BEEN SELECTED TO PROVIDE A SUBSTANTIALLY-SOLIDSTORAGESTABLE NUTRITIOUS PET FOOD AFTER COOKING THE RESULTING ADMIXTURE,(2) SUBJECTING THE RESULTING ADMIXTURE TO COOKING CONDITIONS AT ASUPERATMOSPHERIC PRESSURE SUFFICIENT TO PREVENT SUBSTANTIAL EXPANSION OFTHE RESULTING PLASTIC MASS IN THE EXTRUDER, AND (3) EXTRUDING THERESULTING PLASTIC MASS THROUGH A DIE INTO THE ATMOSPHERE, (C)SUPERIMPOSING ONE OF SAID SHEETS ON THE OTHER, AND (D) FORMING THERESULTING SUPERIMPOSED SHEETS INTO A LOAF-LIKE MASS, SAID FORMING BEINGDONE IN SUCH A MANNER AS TO DISTRIBUTE RANDOMLY THE FAT-LIKE PORTION INTHE RESULTING MASS, SAID FORMING TAKING PLACE WHILE THE AVERAGETEMPERATURE OF SAID FIRST AND SECOND SHEETS IS BETWEEN ABOUT 120*C. ANDABOUT 170*F.